|  | 1.5 | Routing and the Different Classes of Routing Protocols
| 1.5.8 | Network convergence
Routing protocols, which are used to determine the best route for traffic from a particular source to a particular destination, are fundamental to dynamic routing. Whenever the topology of the network changes because of growth, reconfiguration, or failure, the network knowledge base also must change. The knowledge needs to reflect an accurate, consistent view of the new topology. This accurate, consistent view is called convergence. When all routers in a network are operating with the same knowledge, the network is said to have converged. Fast convergence is a desirable network feature because it reduces the period of time that routers have outdated knowledge for making routing decisions that could be incorrect, wasteful, or both.